Electric iron



Aug. 14, 1928.

c. B. BACKER ELECTRIC IRON Filed Oct. 20, 1927 2 Sheets-Sheet l Aug. 14, 1928.

C. B. BACKER ELECTRIC IRON Filed Oct. 20, 1927 2 Sheets-Sheet 2 INVENTOR Chr/'579075. BOC/(en ATTORNEY Patented Aug. 14, 1928.

CHRISTIAN IB. BACKER, OF BROOKLYN, NEW YORK.

ELECTRIC IRON.

Application led Octoberr 20, 1927. Serial No. 227,444.

` My invention relates to electrically heated l devices and parieularly-to electric irons.

An object of my invention is to provide a relatively simple, inexpensive .and highly efficient construction for an electric iron.

Another object of my invention is to rovide an 'electric Iiron embodying a meta -encased tubular heating element embedded in a mass of cast iron.

.Another object of my invention is to provide an electric iron embodying a metal-encased tubular heating element and a sheetj metal member for supporting the heating element in its proper operative position, both during the casting operation and thereafter.

Another object of my invention is to provide an electric iron embodying cast-in heating elements in which the danger of unsound castings shall be reduced lto aI minimum.

In practicing my invention, I provide a metal-encased tubular heating element preshaped to comprise a plurality ofv substantially parallel-extending straight portions` located in two planes, a sheet-metal plate,

-of substantially inverted cup-shape, for supporting the t-ubular heating element, a mass of cast metal filling the member of inverted cup-shape and embedding the heating element, and a suitable cover and handle for the iron.

In a modified formv of electric iron, I provide, in addition to the above, a lower sheet- 'metal member of substantially cup-shape invention,

Fig. 5 is a top plan view of the body portion of the iron shown inA Fig. 4, the cover member having been removed, and

Fig. 6 is a view, in rear elevation, of the assembly shown in Fig. 5. .l c D Referring more particularly to the devlce shown in Fig. 1, an elect-ric iron 11. embodies a tubular heating element 12. which comprises an outer metal casing 13, a resistor helix 14 located therein and separated therefrom by a crystalline mass A15 of magnesium hydroxide or oxide. The tubular heating element is 'made in accordance with the method disclosed and claimed in my reissue Patent No. 16,340.

The method thereinA disclosed and claimed mag be briefly described as follows:

resistor wire is woundy into helical form and is then located within an open helix of magnesium strip. The two helices are then located within the outer metal casing 13, fitting loosely therein. This assembly is then vsubjectedftorthe action of either high-temperature and high-pressuresteam, or water, for a predetermined length of time, which changes the initially metallic magnesium to a crystalline mass of magnesium hydroxide or oxide. The initially metallic magnesium swells during this changeand occupies substantially double the initial space. The result of this is that the helix or resistor wire is held tightly within-the metal tube 13 and provides a relatively low thermal-resistance heat path from the resistor wire to the metal casing.

The heatingelement 12 and its metal casing 13 may be bent to any desired shape, such vas that shown in thel drawings, either lbefore the above described treatment has been effected or thereafter. r

As -it is desired to embed the above-described heating element within a mass of cast metal and it is desirable to provide a supporting means therefor I provide a sheetmetal plate 16 which is bent to substantially cup-shape and is of rectangular contour. The bent-over or rim portions thereof, in

two sides of the member 16, are provided with openings therethrough, through which the upper and end portions of the heating element may extend. The member 16 is located within a suitable mold (not shown), which is used in casting a mass 17 of metal around the heating element and around at least a portion 4of the memberY 16 of cupshape. That side of the member 16 located at the forward partv ofthe electric iron is the one which I prefer to also embed in the mass 17, while the rear side thereof, located closely vadjacent to the end portions of the heating element 12, constitutes an outer wall for a` portion ofthe mass of cast metal. The intermediate portion of theV member 16 conshoulder 18 therearound, which shoulder is Voperatively engaged by the lower rim of a cover 19 of usual construction.' The cover -is clamped against the shoulder 18 by a screw bolt 21. A handle 22 is supported on the cover 19 by handle straps 23 and 24, in a manner well known in, the art. I may provide a small spacing plate at the rear portion ofthe mass 17 which isi-clamped thereagainst by a screw 26..Y The outer edge of the plate 25 engages the inner surface of the rear portion of the cover 19 and cboperates with the bolt 21 to maintain the cover in proper operative position on the vmass 17.

The mass 17 of cast iron, the heating element 12 and the member 16 may be called the body portion oftthe iron.

A plurality of terminal pms 27, only bne of which is shown in the drawing, are insulatedly mounted on the cover 19 and have the ends 28: of the resistor 14 connected thereto, in a manner well Yknown inthe art. A terminal pin guard 29 is secured to the rear handle strap 24.

One of the problems connected withthe manufacture of an electric iron of this type isthat of obtaining a sufficiently high per-` centage of sound castings. This problem is accentuated by the fact that the operating or ironing surface of the member 17 may be the upper surface when the member is being 35 cast, so that there is a tendency for this part of the mass to be spongy or porous. If this sponginess extends too deeply into the casting, it may be necessary to discard it, wherebyl there is lost not only the 'casting but also the heating element embedded therein.

-The modification of my invention shown in Fig. 2" of the drawings, tends to avoid the above-mentioned defect. A bottom sheetmetalwplate 31, of cup-shape, is provided', its form being that of the usual electric iron. A mass 32 of metal is cast within this bottom plate which is preferably' made of mild sheet steel, a heating element 33'of the same generall type as hereinbefore described being embedded thereinf An= upper supporting and clamping member 34 is provided, which is made of sheet metal' and of substantially` inverted cup-shape. Thisvelementis 'subst'antially the same as has hereinbefore been described in connectionl with member 16,

with the exception that the rear rim or edge `rportion thereof is providedwith depending integralglange portions 35 which are bent around the metal casing f4 the heating elel n ybent-over portions 35.

ment 33.` Other vportions of the rear rim are recessed downwardly, as shown at 36, to press the tubular heating element into fthe Substantially the same methodv of molding and casting is; employed as was described face.

' top plate 48,

tuted by the members 31, 32, 33 and 34 are located in their normal or upfright positions within a mold. The bottom surface of the membery 31 may be easily .and quickly polished and plated, asi is usual in theart, and will provide a highly eicient ironing sur- A cover 37 is held against the peripheral portion of the member 31 by a single bolt 38, and a handle 39 is supported on the cover by handle -straps 41 and 42. Terminal pins 43 are insulatedly mounted in the rear por- I tion of the cover 37 and have the ends of the resistor wire connected thereto. A guard 44 surrounds the pins 43 and is secured to the rear handle strap 42.

A7 further modification, which is illustrated in Figs.f4 and 6 inclusive, embodies another solution of the problem of obtaining a sufficiently high percentage of castings which are sound at the ironing surface thereof.

The body portion of the iron, in this modiication, comprises a sole plate 45 -which may be cast, machined, polished and plated separate from the other parts of the body portion, a top casting 46 in which is embedded a metal-encased tubular heating element 47, of` the same general character as hereinbefore described, and a top plate 48. The edge portions vof the member 48 arevprovided with openings in the front and. the rear sides thereof, through which the end portions of the heating element 47 may extend to be held thereby, particularly during the molding and casting operations. InA all other respects, the details of construction of the top casting 46, the heating elements 47 and the are the same as have already been described. The top casting is tightly clamped against the machined upper surface of the sole plate 45 by a plurality of studs 49 and nuts 51. A cover 52, of the usual shape and construction, is clamped against the upper peripheral lportion of the sole plate 45 by a single bolt 53. A handle 54 is supported on the cover by handle straps 55v and 56. Terminal pins 57, only one of nwhich is shown in the drawings, are insulatedly mounted at the rear portion of the cover member 42 and have the ends of the resistor wire electrically connected thereto, in al manner well-.known in the art. Afterminal pin` guard 58 surrounds the pins 57 and is Sup ported by the rear strap 56.

lll

As is shown more particularly in Fig.l 5 of I the drawings, the top plate 48 is provided with' depending integral lugs 45 hereinbefore 'mentioned, in connection with, Fig. 2 and1 is provided also with similar depending lugs 59 at the sides theerof which prevent lateral,

movement of the heating element, 'as well as -support the heating element by `the return-bent end portions thereof, these members operating in substantially the same manner as do the portions 35. Recesses 36 are provided, as was hereinbefore described in connection with the member 34 shown in Fig. 2.

I have found that it is possible to manufacture an electric iron of this type at a reiatively small expense and I ind also that it is possible to obtain a relatively high percentage of sound castings, thereby making the loss of castings and embedded heating elements relatively small.

As the hereinbef'ore described metal-encased tubular heating element is a nhighly efficient one in that the temperature gradient from the resistor wire to the metal casing is relatively small, and as it is possible to eii'ect a close engagement of the cast metal with the outer surface of the metal casing, as by tinning the same before the casting 'operation, I nd that a device of this kind will operate with but a relatively small temperature adient between the resistor and the ironing surface of the body portion.

Various modifications may be made in the device embodying my invention without departing from the, spirit and the scope thereof, and I desire, therefore, that only such limitations shall 1be placed thereon as are imposed by the prior art or are vset forthin the ap ended claims.

I claim as my invention:

1./ In an electric iron, in combinatiom-a tubular heating element, a mass bf castinetal embedding said heating element, and

a sheet-metal top plate covering a. portion of said mass of cast-metal for holding said tubular heating element in predetermined position in saidmass of cast metal.

2. In an electric iron, in combination a mass of cast metal, a metal-encased tubu a-r heating element embedded in said mass, and a sheet-metal' top plate of substantiall inverted cup-shape for supporting said heating element 'and for preventing movement thereofinany one of three major directions.

3. In an electric iron, in combination, a mass of cast metal, a metal-encased tubular heating element embedded in said mass, and a sheet metal top plate of substantially inverted cup-shape, a portion of the rim being also embedded in the cast metal for supporting the heating elementJ in proper operative position. f

4. In an electric iron, in combination, a mass of cast metal, a metal-encased tubular heating element 4embodying a plurality of return-bent portions located in two diier-,v

ent planes embedded in said mass and a sheet-metal top plate, of inverted cup-shape, having openings in the rim portion through 5. In an electric iron, in combination, a sheet-meta1 member of substantially cup'- shape,'a mass of cast metal therein, a metalencased tubular heating element embedded in the mass of cast metal, and an uppersheet-metal member of substantially inverted cup-shape constituting a portion of the upper surface of said mass of cast metal CHRISTIAN B. BACKER.

which the upper portions of. the .tubularf heating element extendto beheld thereby. 

